The present invention relates to a process for synthesizing an ionic metal complex that can be used as a supporting electrolyte for lithium batteries, lithium ion batteries, electrical double-layer capacitors and other electrochemical devices, a polymerization catalyst for polyolefins and so forth, or a catalyst for organic synthesis.
Ionic complexes, such as PF6−, BF4− and AsF6−, formed by bonding of Lewis acids with F ion have been used in applications such as supporting electrolytes for electrochemical devices, polymerization catalysts for polyolefins and so forth or catalysts for organic synthesis due to their solubility and ion dissociation characteristics and their high activity in reactions.
As the application range of these ionic complexes becomes increasingly diverse, efforts are being made to search for the optimum ionic complex for each application, and these ionic complexes are being required to have properties including heat resistance, hydrolysis resistance, low toxicity and recycleability. Under such condition, there have been proposed many complexes in which an organic ligand is bonded to the central element, in addition to conventional complexes in which a simple element (e.g., fluorine and oxygen) as a ligand is bonded to the central element.
There are various processes for synthesizing ionic complexes. For example, it is possible to use a neutralization reaction between (a) a hydroxide of an element corresponding to the central element and (b) a ligand having an active hydrogen of a high acidity. As another example, it is possible to use a desalting reaction between (a) a halide of an element corresponding to the central element and (b) a ligand (e.g., alkali metals) having high degree of dissociation. Depending on the combination of ligand and central element, however, reactivity may become too low to synthesize ionic complexes. Thus, it may become difficult to obtain the originally designed complexes.